The most important weaknesses of perhaps the most successful exponent of pedal driven vehicles, viz. the conventional bicycle, can be considered to be the lack of comfort and the low speed obtainable in comparison with motorized vehicles. Both weaknesses are due to the driving power generated by the rider being low compared with the resistance of the air arising at increased speed and said power also being insufficient for the heavy vehicle weights as a result of efforts to improve the seating position of the rider or increase the comfort in other respects. The introduction of heavy equipment as power transmission devices, steering mechanisms, bodies etc. can be mentioned as examples in this respect.